Upgrade from 11.5.10.2 to R12.1.1

We are upgrading our EBS from 11.5.10.2 to R12.1.1.

We are facomg couple performance issue on some of the upgrade scripts. If any one has faced issue related to below scripts and found some effective solution in redcuing the time. Please let us know.

Script Name   Time Taken in hrs.
===================================
ar120pay.sql  3.5
ar120adjl.sql  5
apxlaupg.sql  5
arupgadjum.sql  5
ar120recpl.sql  9
zxaptrxmigupd.sql 9
ar120gir.sql  20
adsstats.sql  6
ar120ent.sql  36
apilnupg.sql  3
ibyccupd.sql  3
ar120axrec.sql  14
ar120lclcsu.sql  3

Thanks

Praveen